【技术回眸】莲花79——不止于地效（上）

In 2022, Formula 1 embarks on a new ground effect era amid a sweeping new set of rules changes. In this article first published in August 2018, Mark Hughes and Giorgio Piola look at the technological tour de force that was the Lotus 79 – the car that famously took Mario Andretti to the 1978 drivers’ title, the first to be claimed in a Formula 1 car featuring ground effect technology…

2022年，伴随着一系列新规改变，F1迎来了全新的地效世代。在本文中，Mark Hughes和Giorgio Piola将带您领略一辆工程学杰作——莲花79。作为F1史上首辆运用地效技术的神车，她将安德雷蒂抬上了1978赛季的总冠军王座。

The idea of using the underside of a racing car to generate negative pressure and effectively suck the car towards the track had first been exploited in the Can-Am sports cars series in the 1960s. But they were cars with wide, wheel-enclosing, bodywork.

早在1960年代，利用赛车底部产生负压，进而将车牢牢吸在赛道上的想法就已经出现并被使用在了Can-Am系列赛中。不过与F1不同，Can-Am赛车都有着宽宽的车身，并且也是闭轮式的。

Getting the principle to work on a skinny-bodied, open-wheel single seater initially seemed unfeasible. The car which made that breakthrough was the Lotus 78 of 1977, which ushered F1 into the era of ground effect. Forty years ago, the 78’s successor, the Lotus 79, became the first ground effect car to win the world championship, with Mario Andretti at the wheel.

想要让这种原理在窄车身的单座开轮赛车上奏效，最初看起来并不可行。1977年，莲花78成为了第一辆吃螃蟹的赛车。也正是她，引领F1走向了地面效应的时代。40年前（译者注：本文写于2018年），莲花78的继任者莲花79横空出世。她成为了首辆地效冠军车，而马里奥·安德雷蒂也成为了首位开着地效车赢下世界冠军的车手。

The proportions of the 78&79 were very different to those of its contemporaries, and therein lay the clue to the radically different way its aerodynamics worked.

莲花78/79的车身比例和同时代的竞争对手大相径庭，而这其中蕴含着赛车在气动工作方式上的本质不同。

The central tub was unusually narrow and the sidepods took up a far bigger proportion of the car’s width, while running along the bottom of those sidepods were skirts – brushes initially, later solid nylon.

从宽度上来看，赛车中间的盆状结构异常狭窄，而两边的侧箱相比之下占比要大得多。沿着侧箱底部的是侧裙结构：它们最早只是一排毛刷，后来改成了实心尼龙材质。

Those skirts were to make a seal between the underbody and the road, a crucial part in propagating negative pressure beneath the car. That negative pressure was created by the internal shaping of the sidepods, which had an opening at the front, close up behind the front suspension, ostensibly to feed the radiators that were placed there.

侧裙能在车底和赛道间形成密封区，这块密封区对在车底传播负压至关重要。负压由侧箱内部构型产生：它前部有一开口，在前悬架后闭合。表面上，这种设计是为了给那儿的散热器送气。

However, it was the placement and angle of those radiators, and the shaping of the auxiliary fuel tanks also housed within the sidepods, that created the internal venturi shape so crucial in exploiting the airflow.

然而事实上，正是这些散热器的摆放位置和角度，与同在侧箱内的备用油箱的形状一道，为底板文丘里管式的形状创造了空间。这对充分利用气流至关重要。

The channel the air passed through changed in section as it went back, with a narrow inlet opening into a central ‘throat’ and then a further sudden expansion into a diffuser at the sidepod exit just ahead of the rear wheel and suspension.

空气向后流动时，地效通道的形状也随之改变：气流通过狭窄的进气口流入中间的“喉道”。随后通道突然扩大，使气流流入位于侧箱出口，后轮和悬挂前的扩散器内。

Airflow follows the Bernoulli principle whereby the pressure reduces as its speed increases – the venturi shape manipulating the airflow to accelerate and thereby reduce the pressure. But further than that, the close proximity to the ground of the sidepod’s entry massively magnified the effect by accelerating the air as it was sucked through the small gap between track surface and the bottom of the radiator.

气流遵循伯努利原理，即流速越快，压力越小——上文中文丘里管式的形状正是通过加快气体流速减小压力的。而不仅如此，空气被吸入散热器底部与地面的狭小间隙中后，流速进一步加快。这大大加强了侧箱入口紧贴地面带来的效果。

The increase in air speed as the gap between the road surface and opening is narrowed is vastly more than proportional – i.e. it speeds up very suddenly indeed as the gap closes to almost nothing (hence ‘ground effect’).

随着地面与地效通道的间隙逐渐缩小，气流流速的增加远超比例。也就是说，间隙缩小到近乎为零时，空气会突然加速（因此这种现象被称为“地面效应”）。

With the skirts then preventing the air from escaping out of the sides, the acceleration of the air through the channel – and therefore its pressure reduction – was spectacular. This lower pressure applied across the full width of the floor.

侧裙能防止气流从两侧流出，因而空气流经通道的加速，以及进而带来的降压效果令人咂舌。这些产生的低压最终作用于整个底板。

The difference between the underfloor’s air pressure and that of the much higher-pressure freestream airflow above meant the car was effectively being sucked to the ground. Furthermore, that downforce created hardly any drag, unlike that created by the upper body wings pressing down upon the car.

车底和车身之间巨大的气压差意味着赛车可以牢牢贴地飞行。此外，不同于在车身上安装翼片，通过地面效应产生的下压力几乎不会带来任何额外阻力。

未完待续……

摘自F1官网

翻译：mrysdy